sql server update table from another table

number of rows affected.Let's look at the statement that creates the table variable:Copy CodeThe code is as follows:DECLARE @News Table(news_id int not NULL,Newstitle varchar (100),Newscontent varchar (2000),Newsdatetime datetime)Comparing temporary tables and table variables can be done through SQL selection, insert,

stability Lock (SCH-S): Maintains schema stability and does not block access to data when generating execution plans. Schema modification Lock (SCH-M): Used in DDL operations. Block access to object data when the schema is being changed. Use AdventureWorks2008 BEGIN TRAN CREATE TABLE MyTable (ID INT, NAME VARCHAR (), COUNTRY VARCHAR ()) SELECT Resource_type , Request_mode, resource_description from sys.dm_tran_locks WHERE resource_type

transaction. Tablockx: Specifies that an exclusive lock is used on the table, which prevents other transactions from reading or updating the table's data until the end of the statement or the entire transaction.UPDLOCK: Specifies that the update lock is set when reading data in the table (update lock) instead of the s

then we can break down each point of the key.Partitioning is to split a table data into sub-collections, that is, to split a data file into multiple data files, but the storage of these files can rely on a filegroup or multiple filegroups, because more than one filegroup can increase the database access concurrency, but also can be different partitions configured to different disks to improve efficiency , the recommended partition is created with the

above code, we can see that this table has the characteristics of the general table--there is a primary key, and the primary key is also a clustered index. As mentioned earlier, a partitioned table is a partition condition for a field, so you cannot create a clustered index other than this field. Therefore, to convert a normal

' andParent_obj=a.ID andNameinch ( SELECTName fromsysindexesWHEREIndidinch(SELECTIndid fromSysindexkeysWHEREId=a.ID andColid=A.colid))) Then '√' Else "' End, type=b.name, number of bytes occupied=a.length, Length= ColumnProperty(A.id,a.name,'PRECISION'), number of decimal digits= IsNull(ColumnProperty(A.id,a.name,' Scale'),0), allow null= Case whenA.isnullable=1 Then '√'Else "' End, the default value= IsNull(E.text,"'), field description= IsNull(g.[value],"') fromsysc

statement, you can recite this kind of Chinese in your heart, easy to remember, and not prone to mistakes and missing some keywords--Modify Column Properties--Modify the properties in the table, using the Alter--Change the column length of the name to 10 and change the date of birth from data to Datatime Usetest_427GOALTER TABLEXSBALTER COLUMNStudentnameChar(Ten)--use ALTER to indicate update modifications

Suppose we have two tables, a table that holds product information for the product table, which contains price list prices; Another table is the Productprice table, and we want to update the Price field in the Productprice table t

1. Database Table Locking Principle 1.1 currently, the C/S and B/S structures all involve multiple users accessing the database. Each time point there are thousands of users accessing the database, and the same data is also accessed, this may cause data inconsistency or dirty Data Reading. 1.2 acid principles of transactions 1.3 locks are an important part of relational databases. The database must have a locking mechanism to ensure

In SQL Server performance tuning, there is an aspect problem: How do you work with temporary datasets in code that takes a long time or is frequently called? Table variables and temporary tables are two choices. Remember that a large number of temporary data set processing requirements have been seen in SQL

First is three tables, CNO corresponds to the course, where I pasted. Primary table Name list Follow the general query SELECT S.sname, C.cname,s2. Scgrade From S INNER JOIN SC s2 on S2. SNo = S.sno INNER JOIN c c on c.cno = s2. CNo So the result is this. But this is not the result I want to see. We want to see this result: So what do we do?The first method of writing: Copy Code code as follows: SELECT W.sname, SUM (c

SQL Server insert efficiency (heap table vs clustered index table) "Which of the following is more efficient for SQL Server insert operations in heap tables or clustered index tables? Why is it high ?" Some colleagues have aske

Label:1. Understand the database and create new: 1) Open the database and connect to the server. 2) service type without tube. 3) server name: Make a point "." Indicates that the server is on the local computer and, if it is hosted on someone else's server, enter the server

The following is an example:Two tables, SourceTable and TargetTable, are logon tables. If the user accesses the login table, update the authorization level of the authorization table. Otherwise, authorization 0 indicates the visitor. The SQL statement is as follows:-- SourceTable: logon

The database has two fields in the wrong position, you want to change them. Because there is no database write permission, it needs to be implemented with SQL statements. Originally thought to be simpleUpdate table A set a. Field a= (select B field from table where id=?), set a. Field b= (Select a field from table wher

(SELECT * from INSERTED) and is EXISTS (SELECT * from DELETED)----Insertbeginset @acti on= ' INSERT ' endelse IF not EXISTS (SELECT * from INSERTED) and EXISTS (SELECT * from DELETED)----Deletebegin SET @actio n= ' DELETE ' endelse IF EXISTS (SELECT * from INSERTED) and EXISTS (SELECT * from DELETED)-----updatebegin SET @action = ' UPDATE ' Endselect row_number () over (ORDER by Dataareaid) rowid,description,code,category,getdate () Modifieddatetime,

SQL Server recovery table-level data details, SQL Server details In recent days, the company's technical maintenance staff frequently asked me to restore the database, because they always have fewer where conditions, resulting in unrecoverable consequences for the

SQL Server traversal tables are typically used in cursors, and SQL Server can easily loop through a cursor to implement SQL Server traversal of records in a table. This article will int

Recently, a friend of mine told me that the execution of many stored procedures in his database has timed out. let me show him why. I saw that many temporary tables and variable tables were used in his stored procedures. so I told him that I was too late. Using temporary tables or variable tables during storage can improve the speed and result in adverse effects. then, I gave him several examples for him to view and modify his database. Is the table v

Create a good rule name -- parameter 2 is bound to a specific table. Column Name sp_bindrule score,' student grades, score ' 9. Dismiss and delete rules Unbind the rule to remove!!! -- Unbind --parameter- specific binding columns ' student performance. Score ' -- Delete Rule Drop Rule Score 10. Data graphs better display the relationships between tables ~ ~ 1. Right-click the new diagram 2. Add all the tables 3. Drag the column of the select